Compositions containing platinum

ABSTRACT

This invention describes a composition which is active against ADJ/PC6 tumors in mice comprising a cis co-ordination compound of platinum having the structure   IN WHICH X and Y are halogenoid groups which are the same or different and A and B are the same or different alicyclic amine groups co-ordinated to the Pt through their N atoms each having the general formula

United States Patent [1 1 Tobe et al.

[451 July 1, 1975 1 COMPOSITIONS CONTAINING PLATINUM [73] Assignee: Rustenburg Platinum Mines Limited, Johannesburg, South Africa [22] Filed: Apr. 9, 1973 [21] Appl. No.: 349,186

[30] Foreign Application Priority Data OTHER PUBLICATIONS Lifschitz et al., Zanorg Chem. 233 (1937), p. 12, 32, 33, Ginehim l-landbuch der Amorganishen Chemie 68D (1957), Verlay Chemie Wunheim pp. 266-278. Chemical Abstracts 74 (1971) No. 68420v. Rosenberg et al., Nature 222 (1969) pp. 385-386.

Primary Examiner-Arthur P. Demers Attorney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT This invention describes a composition which is active against ADJ/PC6 tumors in mice comprising a cis coordination compound of platinum having the structure A X \Pt in which X and Y are halogenoid groups which are the same or different and A and B are the same or different alicyclic amine groups co-ordinated to the Pt through their N atoms each having the general formula cyclo-C,,R Nl-l in which n may vary from 3 to 7 and in which all of the R groups are either the same of different and are preferably all hydrogen but may be selected from the group consisting of hydrogen, alkyl, aryl, alkanyl, aralkyl, halogen, pseudohalogen, hydroxy, carbonyl, formyl, nitro, amido, amino, sulphonic acid, sulphonic acid salt, carboxylic acid, carboxylic acid salt, and substituted alkyl, aryl, alkaryl and aralkyl groups.

14 Claims, No Drawings 1 COMPOSITIONS CONTAINING PLATINUM This invention relates to new compositions of matter which are active against ADJ/PC6 tumours in mice and to methods of preparation and use of such compositions.

According to the present invention the composition comprises a cis co-ordination compound of platinum having the structure:

in which 11 may vary from 3 to 7 and in which all of the R groups are either the same or different and are preferably all hydrogen but may be selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, halogen, pseudohalogen, hydroxy, carbonyl, formyl, nitro,

2 amido, amino, sulphonic acid, sulphonic acid salt, carboxylic acid, carboxylic acid salt, and substituted alkyl, aryl, alkaryl and aralkyl groups.

Although R groups other than hydrogen are not normally preferred, they may be used and may comprise lower alkyl such as methyl or ethyl groups or a solubilizing group such as a sulphic acid group. Solubilizing groups as substituents such as carboxylic acid, sulphonic acid, carboxylic acid salt, sulphonic acid salt, e.g. the sodium, potassium or lithium salts, are sometimes appropriate when the clinical conditions require high solubility.

Throughout the specification and claims, the term halogenoid is used to mean halide or pseudohalide such as cyanide, cyanate, thiocyanate or azide.

Cis-dichloro diamine platinum (II) is a known antineoplastic compound having a therapeutic index of 8.1. The biological data for the bis(cyclopropylamine), bis(cyclobutylamine), bis(cyclopentylamine), bis(cyclohexylamine) and bis(cycloheptylamine) derivatives of the cis dichloro Pt (II) complexes, i.e.

A Cl

where A and B are identical and consist of C C alicyclic primary amine, are given below with comparative data for chemically similar compounds when tested against ADJ/PC6 plasma cell tumour in mice:

SUMMARY OF ACTIVE PLATINUM COMPOUNDS ON THE ADJ/PC6 PLASMA CELL TUMOUR Mean Tumour Dose Wt. As 7! v. Re. Name Formula* Veh1cle Rt. (single) so sn Tl O Control lnhib mark ml/ 12 il/ i Y cis-DichlorolPnNHu-z zl 011 i.p (H5625 1.60 13 11.1 110.7 1 .7

diammine 0.3125 50 50 For platinum (ll) 0.625 69 31.0 com- 1.25 16.4 83.4 puri- .'Z.5 2.4 97.6 son 5 0.7 99.3 10 0 101) 1D/3 20 3D/3 30/3 Cl 011 i.p 11.3125 211s 14.1 6.9 75.1 24.9 Dichloro[(DL)- 0.625 113.1 l6.'-) cyclohcxane CH: 1.25 34.9 65.1 For (trans)-l.2- P CIH I j S diamine] 0.4 99.6 coml i [1 CH CH 5 0.8 99.2 pari- 111 0.4 99.6 son Cl NHL, CH: 20 30 3 40 30/: /CH2-CH2 O1l i.p 3.125 10.8 14.! 13.] 68.6 31.4 Cl NH I 6.25 26.0 74.0 i fi P 12.5 s 9 94 1 For t Pt 25 '219 971 com- Plmmum 2 1.11 99.0 pari- Cl NH\ 1.5 98.5 son CHr z 200 3D/3 A CiS-diChIOl'O- i 1 2 7 g 5 -7 Q hiswycllnprw MH /Cl O1l p 2.; ...3 6. -411 pyl-amme) Pl 5 97 5 platinum (ll) NH/ [b 9 :5 2 20 1.5. 9115 V 411 1.5 98.5

SUMMARY OF ACTIVE PLATINUM COMPOUNDS ON THE ADJ/PC6 PLASMA CELL TUMOUR -Continued Dose Mean Tumour Name Formula* Vehicle Rt. i l FD... l D Wt. As 7( Remg/Kg mg/Kg mg/Kg TI 01 Control lnhib mark C1$-dichloro Oil 1.p l 10 62.81250 125 3.4 96.6 brs-tcyclohcxylc] 50 2.0 98.0 amine 2 250 1.5 98.5 (11) P1 1250 0.5 99.5 platinum cis-dichloro- O c] Oil i.p 1.5 2 4 480 200 21 ."1 78.7 bis-cyclopcn- 2 3.125 3.8 96.2 tylaminc) Pt 6.25 1.6 98.4

. 2 s platlnum (ll) O Z lD/ 400 0.8 99.2 lD/3 800 3D/3 3200 3D/3 DlClllOrOblS- 2 011 1.p 6 6 67 11.1 1.6 98.4 (cyclohutyl- Pt\ ?(S)0 1.6 98.4 ammc) 3D/3 platinum (111 o Nl-l C 750 3D/3 O-NH C1 cis-dlchloro- 2 O11 1.p 5 l8 625 34.7 41.5 58.5 bis-(cyclohep- Pt 25 2.2 97.8 tylamrnc) c1 25 1.6 98.4 platinum (II) 625 2.7 97.3

A repetition of the tests gave the following resultsf The highest number of the series so far tested, the biscylohexylamine complex has the best therapeutic index so far seen with the platinum compounds. The value greater than 267 is, in fact, the highest index ever obtained in this system and makes the compound more than thirty times more selective against this tumour than the platinum complex at present on clinical trial.

In previous screening of compounds for anti-tumour activity, the PC6 tumour has been shown to be particu' larly sensitive to alkylating agents and especially to clinically useful ones such as melphalan and cyclophosphamide which have therepeutic indices of 166 and 136 respectively. The finding that the cis-dichlorobis- (cyclohexylamine) and bis(cyclopentylamine) platinum (II) complexes are highly active and nontoxic against the plasma cell tumour represents an important contribution The bis(cyclopentylamine) complex causes a 30% increase in survival time at optimum dose with the TL X 5 Lymphoma and causes regression of the sarcoma 180 at tolerated dose levels.

METHODS OF BIOLOGICAL TESTING The new compounds were assayed against female BALB/c mice bearing the established ADJ/PC6A tumour by the method previously described in the article: Rosenoer, V.M., Mitchley, B.C.V., Roe, F.J.C. and Connors, T.A. Walker carcinosarcoma 256 in study of anti-cancer agents. Cancer Res. SuppL, 26, pt.2, 937-941, 1966. Tumours were transplanted subcutaneously by means of tumour fragments and treatment commenced at 24 days after implantation when the tunours were approximately 2 gm in weight. In preliminary tests, six control animals were used and several groups of three treated animals. Several dose levels were given at five fold dose spacings and ranged from lethal to non-tumour inhibitory, allowing the calculation of LD and ED (minimum dose to cause tumour regression) in the one experiment. The ratio LD50/ ED is a therapeutic index and is a measure of the selectivity of the compound as an anti-tumour agent. Agents found to be active were then further tested using the same protocol but smaller intervals (two fold) between doses. This enabled the calculation of LD and ED with narrower fiducial limits. All compounds were administered intraperitoneally as a single dose suspended in arachis oil. The tumour inhibitory cis-dichlorodiammine platinum (ll) served as a positive control. Tumours were dissected out and weighed ten days after drug treatment.

The tests were carried out on Balb/C white mice filtered from the solution and dissolved in hot concen trated HCl. The resultant yellow solution was refrigerated for three days and the lemon yellow, woolly needles which precipitated were filtered off, washed with water, acetone and ether and dried in vacuo (C. 18.7;

using three test mice for each dose level and a mini- 5 mum of Six untreated Control mice H, 3.7; N, 7.6; Cl, 18.9%. C H Cl N Pt requlres C,

An ADJ/PC6 plasma cell tumour taken from a sacri- N f ficed mouse is dissected free of superfluous tissue and at c l. A cis co-ordinatron compound of platinum havmg out under sterlle condltlons into approximately 10 m1lth 10 6 structure ligram s1ze pieces. The tissue pleces were then 1mplanted by trocar in the left axillary region subcutaneously, in new mice. The mice were, on the average, apn proximately seven weeks old and weighed 18-20 grams. Taking day 0 as the day ot treatment (24 days p; after tumour implantation), the animals were sacrificed p on day 10. The tumours were excised and weighed and J i the ratio of the weights of the tumours in the treated animals to the control set of animals was obtained.

In the test animals the compounds were injected on m wh1ch and Y are halogen groups whlch f the 2 same or dlfferent and A and B are the same or different day 0 in 01], mtraperitoneally. The volume of the lIl ]C- l l 100 b d h ahcychc amme groups co-ordlnated to the Pt through m o y welg their N atoms each having the general formula:

ED is the minimum dose causing a 90% regressron in the size of the tumour. LD is the dose level causing cycloC,,R NH 50% deaths of h animals- The therapeuP? Index 15 25 in which n may vary from 3 to 7 and in which all of the sn/ su 4 l5 a 0f the selectlvlty of the R groups are either the same or different and are se- Compound questmn treatmg the tumour- I13/3 lected from the group consisting of hydrogen and means one death in three animals; 3D/3means three methyl a d ethyL deaths in 3 animals etc. 2. A compound according to claim 1 in which X and These results show that compounds according to the Y are identical. invention give exceptionally good results for anti- 3. A compound according to claim 2 in which X and tumour activity and compare very favourably with Y are oth Chloride. l chemically similar but structurally different coml 9 Glam 3 wh1ch A and pounds such as the dichloro [(DL) cyclohexane B are ldentlcal ahcychc (trans)-l,2-diamine1platinum (II) and the cis dichloro A f p l w g to clalm 1 m wh1ch A and bis(pyrrolidino)-platinum (ll) given in the table of re B are dlfferem ahcychc f o 6. A compound accordmg to cla1ms 4 1n Much the sults for comparison. ahcychc amines are C-subst1tuted in one or more posi- PREPARATION OF PLATINUM COMPLEXES tions. The cis-dichlorobispyrrolidine, cyclopentyl-amine, A compound accordmg to clams 4 m whlch R l b l d l h l 1 ti m n groups are hydrogen. eye 0 uty amme an s p a nu l 8. A compound according to claim 6 in which the C- Complexes prepare y t e genera substituent is selected from the group consisting of method: Equ1valent amounts (ca. 1 m1ll1mole)ofpotasmethyl and ethyl. sium tetrachloroplatinate (l1) and each amine pyrroh- 9. A compound according to Claim 4 in which n 3 dine (pyrr) cyclopentylamme (cypam), cyclobutylad R is hydrogen. mine y and cyclohexylammfi y were 10. A compound according to claim 4 in which n stirred in aqeuous solution at room temperature for 4 and R is hydrogen several hours. Yellow crystalline precipitates were fil- 11 A compound according to claim 4 in which n tered off, washed with concentrated HCl (not neces- 5O 5 d R i h d sary for pyrr). Water. methanol, acetone and i hyl 12. A compound according to claim 4 in which n ether and dried in vaccuo. 6 and R is hydrogen.

C/( H'/: N'/( C17: Complex Found Req. Found Rcq. Found Rcq. Found Req.

PLCI pyrr 23.5 23.5 4.2 4.5 7.0 6.9 17.2 17.4 Pt.Cl cypam 27.2 27.5 5.0 5.] 6.6 6.4 l5.4 l 6.3 PLChcybum 23.4 23.6 4.4 4.5 7.1 6.9 17.3 17.4 Phcl cyhum 31.1 31.0 5.6 5.7 6.3 6.0 15.1 15.3

ClS-DICHLOROBIS(CYCLOPROPYLAMINE)- 13. A compound according to claim 4 1n wh1ch n PLATINUM (ll) 7 and R is hydrogen. cyclopropylamine hydrochloride (0.7l6g) in water i:i lf p f i i g cis dllchloro [317(9)]- (5ml) was added to a filtered solution of K PtCl. 7 i ig l z ex F g g (1.68g) in water (15ml). Sodium bicarbonate (0.682g) e S cps O a l 0 6 eye 0a 1p a amme y mwas then added to liberate the base and the solution was allowed to stand at room temperature for one day. The mixture of black powder and yellow crystals was chloride to a solution of an alkali metal chloroplatinate, allowing to stand, dissolution of resultant solid in concentrated hydrochloric acid solution and refrigeration in order to precipitate the complex. 

1. A CIS CO-ORDINATION COMPOUND OF PLATINUM HAVING THE STRUCTURE
 2. A compound according to claim 1 in which X and Y are identical.
 3. A compound according to claim 2 in which X and Y are both chloride.
 4. A coupound according to claim 3 in which A and B are identical alicyclic amines.
 5. A compound according to claim 1 in which A and B are different alicyclic amines.
 6. A compound according to claims 4 in which the alicyclic amines are C-substitUted in one or more positions.
 7. A compound according to claims 4 in which all R groups are hydrogen.
 8. A compound according to claim 6 in which the C-substituent is selected from the group consisting of methyl and ethyl.
 9. A compound according to claim 4 in which n 3 and R is hydrogen.
 10. A compound according to claim 4 in which n 4 and R is hydrogen.
 11. A compound according to claim 4 in which n 5 and R is hydrogen.
 12. A compound according to claim 4 in which n 6 and R is hydrogen.
 13. A compound according to claim 4 in which n 7 and R is hydrogen.
 14. A method of preparation of a cis dichloro bis (cycloaliphatic amine) platinum (II) complex comprising the steps of addition of the cycloaliphatic amine hydrochloride to a solution of an alkali metal chloroplatinate, allowing to stand, dissolution of resultant solid in concentrated hydrochloric acid solution and refrigeration in order to precipitate the complex. 